Intent to Ship: WebAssembly Garbage Collection (WasmGC)
Emanuel Ziegler
Dear API owners,
Following the continued experiment for Garbage Collected WebAssembly (WasmGC), we plan to ship the feature in M119 after the positive vote to phase 4 by the WebAssembly Community Group today.
The feature has shown very good performance with reasonable compromises. The findings from the origin trial are summarized in a public document.
This feature is tied to the Function References proposal which is a de-facto part of WasmGC (no current use outside of the proposal, hard requirement for WasmGC) and only listed as a separate proposal for historic reasons. The Function References proposal has therefore also been voted to phase 4 on the same day as WasmGC.
We plan to launch the feature in the following manner:
End the current origin trial with M118 as its last milestone
Refactor the binary instruction representation to match the final spec (incompatible change)
Ship the feature with M119
Our data from the trial has shown that there is a need for fast string interoperability with JS that this proposal does not address. We plan to launch a new experiment investigating different approaches to this problem (see separate I2E mail).
End the current origin trial with M118 as its last milestone
Refactor the binary instruction representation to match the final spec (incompatible change)
Ship the feature with M119
Contact emails
ad...@chromium.org, jkum...@chromium.orgExplainer
https://github.com/WebAssembly/gc/blob/master/proposals/gc/Overview.mdhttps://github.com/WebAssembly/function-references/blob/main/proposals/function-references/Overview.md
Specification
https://github.com/WebAssembly/gc/tree/main/proposals/gcSummary
The GC proposal adds efficient support for high-level managed languages to WebAssembly, via struct and array types that enable language compilers targeting Wasm to integrate with a garbage collector in the host VM. In Chrome, enabling this feature implies enabling Typed Function References, which allow function references to be stored in the aforementioned structs and arrays.
Blink component
Blink>JavaScript>WebAssemblySearch tags
wasm, webassembly, gc, managed objects, wasmgcTAG review
https://github.com/w3ctag/design-reviews/issues/814TAG review status
Issues addressedRisks
Interoperability and Compatibility
Gecko: Positive
WebKit: No signal
Web developers: Positive Google Sheets, which is currently compiling Java to JavaScript, is experimenting with using WasmGC to speed up their calculation engine. JetBrains is working on a Kotlin -> WasmGC compiler. Dart is working on a Dart -> WasmGC compiler, in collaboration with Flutter.
Other signals:
WebView application risks
Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?
Debuggability
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?
NoIs this feature fully tested by web-platform-tests?
NoFlag name on chrome://flags
Finch feature name
NoneNon-finch justification
The feature does not enable any functionality without the module being explicitly compiled for that feature. We therefore chose to use an origin trial to evaluate its suitability and stability. This allowed websites that want to try this feature to opt in and do their own A/B comparisons.
Requires code in //chrome?
FalseTracking bug
https://bugs.chromium.org/p/v8/issues/detail?id=7748Launch bug
https://launch.corp.google.com/launch/4231622Estimated milestones
| OriginTrial desktop last | 120 |
| OriginTrial desktop first | 112 |
| OriginTrial Android last | 120 |
| OriginTrial Android first | 112 |
Anticipated spec changes
Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/6062715726462976Links to previous Intent discussions
Intent to Experiment: https://groups.google.com/a/chromium.org/g/blink-dev/c/HDbvHCVFSW0Intent to Extend Experiment: https://groups.google.com/a/chromium.org/g/blink-dev/c/7F_daEqGQAY
Intent to Ship: https://groups.google.com/a/chromium.org/g/blink-dev/c/7F_daEqGQAY
Mike Taylor
On 9/12/23 9:22 PM, 'Emanuel Ziegler' via blink-dev wrote:
Dear API owners,
Following the continued experiment for Garbage Collected WebAssembly (WasmGC), we plan to ship the feature in M119 after the positive vote to phase 4 by the WebAssembly Community Group today.
The feature has shown very good performance with reasonable compromises. The findings from the origin trial are summarized in a public document.
This feature is tied to the Function References proposal which is a de-facto part of WasmGC (no current use outside of the proposal, hard requirement for WasmGC) and only listed as a separate proposal for historic reasons. The Function References proposal has therefore also been voted to phase 4 on the same day as WasmGC.
We plan to launch the feature in the following manner:
End the current origin trial with M118 as its last milestone
Refactor the binary instruction representation to match the final spec (incompatible change)
Ship the feature with M119
Our data from the trial has shown that there is a need for fast string interoperability with JS that this proposal does not address. We plan to launch a new experiment investigating different approaches to this problem (see separate I2E mail).
Contact emails
ad...@chromium.org, jkum...@chromium.org
Explainer
https://github.com/WebAssembly/gc/blob/master/proposals/gc/Overview.md
https://github.com/WebAssembly/function-references/blob/main/proposals/function-references/Overview.md
Specification
https://github.com/WebAssembly/gc/tree/main/proposals/gc
Summary
The GC proposal adds efficient support for high-level managed languages to WebAssembly, via struct and array types that enable language compilers targeting Wasm to integrate with a garbage collector in the host VM. In Chrome, enabling this feature implies enabling Typed Function References, which allow function references to be stored in the aforementioned structs and arrays.
Blink component
Blink>JavaScript>WebAssembly
Search tags
wasm, webassembly, gc, managed objects, wasmgc
TAG review
https://github.com/w3ctag/design-reviews/issues/814
TAG review status
Issues addressed
Risks
Interoperability and Compatibility
Gecko: Positive
WebKit: No signal
Web developers: Positive Google Sheets, which is currently compiling Java to JavaScript, is experimenting with using WasmGC to speed up their calculation engine. JetBrains is working on a Kotlin -> WasmGC compiler. Dart is working on a Dart -> WasmGC compiler, in collaboration with Flutter.
Other signals:
WebView application risks
Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?
Debuggability
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?
No
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Adam Klein
Can you say more about this?
Web developers: Positive Google Sheets, which is currently compiling Java to JavaScript, is experimenting with using WasmGC to speed up their calculation engine. JetBrains is working on a Kotlin -> WasmGC compiler. Dart is working on a Dart -> WasmGC compiler, in collaboration with Flutter.
Other signals:
WebView application risks
Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?
Debuggability
Can you say more about this?
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?
No
In this case, is this new feature covered by existing wasm test suites?
Presumably this is behind a feature, if an Origin Trial occured, right?
Yoav Weiss
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEvLGc%2B_PnX%3DTXosOwV%3DcpTOCr0w16Xi940o7Rc3%3DWiEm%2BnKoQ%40mail.gmail.com.
Mike Taylor
LGTM2 - thanks Adam.
Chris Harrelson
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/221fb42e-d5f9-424b-97db-82b34b66bf86%40chromium.org.
Thomas Steiner
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw9UpuDt6rP4bgiJa_p9dMc_t%3DR9m8Ei3mjNzuzyBkfaYg%40mail.gmail.com.